The great Harvard psychologist Dan Wegner, who died earlier this year , wrote a famous article entitled ‘How To Think, Say, or Do Precisely the Worst Thing for Any Occasion’. It concerned a very specific kind of mistake, which he labelled the “precisely counterintuitive error” – the kind of screw-up so obviously calamitous that you think about it in advance and decide you definitely won’t let it happen:

“We see a rut coming up in the road ahead and proceed to steer our bike right into it. We make a mental note not to mention a sore point in conversation and then cringe in horror as we blurt out exactly that thing. We carefully cradle the glass of red wine as we cross the room, all the while thinking ‘don’t spill,’ and then juggle it onto the carpet under the gaze of our host.”

This is an example of what psychologists call an “ironic effect”: it’s not just that we fail in our best efforts, but that we fail because of our best efforts. If you hadn’t given much thought to the wine, you’d probably not have disgraced yourself.

Stigmatising obesity makes overweight people eat more, not less. Supporting a good cause on Facebook makes people less likely to give money or time. Interesting thought and something we might have to keep in mind the next time we’re trying to convince people not to do something, we might actually get the opposite result.

In short: if you’re trying to change behaviour or beliefs – your own, or other people’s – don’t assume that the most direct, vigorous or effortful route is necessarily the most effective one. The human mind is much, much more perverse and annoying than that.